Mindfulness, defined as the ability to maintain non-judgemental awareness of present experiences, has emerged as an important predictor of mental well-being. In this study we investigated the cognitive / neurophysiological mechanisms of inhibitory control and response monitoring, considered to be important factors underpinning mindfulness. Participants performed a typical Go/NoGo task while the 64-channel EEG was recorded. Their task was to respond with speeded button presses to standard stimuli and to withhold responses to less frequent lures. The mean amplitudes of a second negative ERP component, peaking around 250 ms after stimulus onset (N2) with a maximum at fronto-central sites, were significantly larger for lures than for standards. Similarly, the following positive component (P3), peaking around 370 ms with a slightly more anterior topography, was enlarged for lures. Interestingly, for withheld responses these components showed variations that depended on the self-reported levels of mindfulness, assessed with the Five Facet Mindfulness Questionnaire: Comparing higher to lower levels of mindfulness, the N2 was significantly reduced, while the P3 was enlarged. The enlarged N2 component in NoGo trials is considered to reflect inhibitory mechanisms, while the P3 has been linked to response monitoring and possibly the preparation for subsequent trials. The pattern of results may thus indicate that higher levels of mindfulness are linked to more efficient inhibitory processes, followed by a more elaborate evaluation of one's own response behaviour. Building on these findings, we predict that meditation practices that foster mindfulness are likely to improve inhibitory and response monitoring mechanisms, partially explaining their wide-ranging beneficial effects. Funding: Funded by the BIAL Foundation (to PM) and a scholarship by the Spanish Ministry of Science and Education (to JPP).